Is editor open sourced?

I clone the source down, and built it well.
But it seems doesn’t contain the editor’s source.
Is editor open sourced? Or I just not found it in my source ?

Hello naive231,

When you mean that you have ‘clone the source down’ do you mean that you downloaded it from Github? The editor is open source but to get the source version, you’ll need to sign up with Github and link your Epic Games account to that Github account. This will get you added to the Epic Games Organization on Github where you can download the source. Once it’s downloaded, all of the source files are included in the Engine/Source directory. You’ll also want to follow the steps here for building it: Building Unreal Engine from Source | Unreal Engine Documentation

I do clone the source by git, not just download it. I built it on linux, everything’s fine, and I thought I can build editor on linux. It turns out that I should run the GenerateProjectFiles.bat in windows to generate the editor’s solution files. Thanks for reply so fast.

In both cases you need to run GenerateProjectFiles (either .sh or .bat), both on Windows and Linux.